Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities
Net income per consolidated statements of income	$ 99,943	$ 54,368
Adjustments to reconcile net income to net cash provided by operating activities:
Credit loss expense, net	(19,331)	51,791
Depreciation and amortization	22,428	19,656
Net amortization of securities	10,780	4,666
Gains on sales of loans, net	(45,625)	(30,361)
Compensation expense, long-term incentive plan	3,395	2,668
Deferred income tax provision	12,500	(19,500)
Proceeds from sales of loans held for sale	1,334,752	1,133,259
Purchases and originations of loans held for sale	(1,220,055)	(1,167,299)
Originations of mortgage servicing rights	(15,201)	(12,396)
Earnings on bank-owned life insurance	(2,418)	(2,544)
Net change in other assets	23,623	(45,712)
Net change in other liabilities	(9,802)	(1,491)
Other operating activities, net	(6,871)	28,447
Net cash from operating activities	188,118	15,552
Investing Activities
Proceeds from maturities, prepayments and calls of securities held to maturity	105,814	79,114
Proceeds from maturities, prepayments and calls of securities available for sale	442,450	249,383
Purchases of securities available for sale	(1,024,649)	(492,067)
Net proceeds from bank-owned life insurance	1,791	592
Net change in federal funds sold and securities purchased under reverse repurchase agreements	50	0
Net change in member bank stock	(1,037)	361
Net change in LHFI and PPP loans	(237,666)	(1,193,397)
Proceeds from sales of PPP loans	353,287	0
Purchases of premises and equipment	(13,920)	(8,638)
Proceeds from sales of premises and equipment	0	3
Proceeds from sales of other real estate	1,167	10,279
Purchases of software	(2,336)	(3,179)
Investments in tax credit and other partnerships	(13,396)	(1,612)
Purchase of insurance book of business	0	(3,097)
Net cash used in business acquisition	0	(4,834)
Net cash from investing activities	(388,445)	(1,367,092)
Financing Activities
Net change in deposits	583,320	2,259,916
Net change in federal funds purchased and securities sold under repurchase agreements	(7,343)	(185,765)
Net change in short-term borrowings	(4,653)	4,062
Payments on long-term FHLB advances	(9)	(34)
Payments under finance lease obligations	(712)	(905)
Common stock dividends	(29,325)	(29,393)
Repurchase and retirement of common stock	(24,990)	(27,538)
Shares withheld to pay taxes, long-term incentive plan	(1,241)	(1,079)
Net cash from financing activities	515,047	2,019,264
Net change in cash and cash equivalents	314,720	667,724
Cash and cash equivalents at beginning of period	1,952,504	358,916
Cash and cash equivalents at end of period	$ 2,267,224	$ 1,026,640